.intro{
    width: 100%;
    height: 786px;
    /* background-color: #74b9ff; */
    background-image: url(../img/index-nav-bg3.png);
}

.banner{
    font-size: 100px;
    color: rgba(255, 255, 255, 0.3);
    font-family:  Lantinghei SC;
    /* 斜体 简洁 */
    
    margin-top: 66px;
}
/* ------------------------------------------------- */
.bg{
    background-color:#eff5f9;
}
/* 大标题 */
.header{
    height: 50px;
    border-bottom: 1px solid grey;
}

.head-logo{
    float: left;
    margin-left: 10px;
}
/* 书籍卡片 */
.book-box{
    height: 192px;
    width: 147px;
    background-color: #505050;
}
/* ---------------------------------------------------- */
/* 锚点需要的 */
a{
    display: block;
}
/* font-------------------------------------------------- */
.big-h{
    margin-left: 10px;
    font-size: 30px;
    float: left;
    margin-top: 5px;
}
.middle-h{
    font-size: 20px;
}

/* 尝试 */
/* #xl{
    display: none;
    position: absolute;
    left: 0px;
    top: 50px;
}

#xl a{
    display: block;
    width: 200px;
    height: 50px;
    font-size: 24px;
    color: orange;
    border: 1px solid #ccc;
} */

.nav ul{
    display:none;
}